The 375 High Pressure PRI relief valve from The Lee Co. in Westbrook, Conn. (www.theleeco.com), provides stable relief flow despite back pressures as high as 850 psig. The valve is constructed of stainless steel with a tungsten-carbide ball. Versions are available in forward and reverse flow and come in cracking-pressure ranges of 3,000 to 5,400 psi. The valve is designed for system pressures up to 5,000 psi. The maximum leakage at minimum cracking pressure or minimum shutoff pressure is 2 ml/min. The valves measure 2.1-in. long and 0.375 in. in diameter. It weighs only 20 gm. All valves are 100% tested and inspected.